ladybird/Userland/Libraries/LibJS/Bytecode/CommonImplementations.cpp
2023-10-27 19:07:22 +02:00

187 lines
8.2 KiB
C++

/*
* Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Bytecode/CommonImplementations.h>
#include <LibJS/Bytecode/Interpreter.h>
#include <LibJS/Bytecode/Op.h>
#include <LibJS/Runtime/DeclarativeEnvironment.h>
#include <LibJS/Runtime/ECMAScriptFunctionObject.h>
#include <LibJS/Runtime/GlobalEnvironment.h>
#include <LibJS/Runtime/ObjectEnvironment.h>
namespace JS::Bytecode {
ThrowCompletionOr<NonnullGCPtr<Object>> base_object_for_get(Bytecode::Interpreter& interpreter, Value base_value)
{
auto& vm = interpreter.vm();
if (base_value.is_object())
return base_value.as_object();
// OPTIMIZATION: For various primitives we can avoid actually creating a new object for them.
if (base_value.is_string())
return vm.current_realm()->intrinsics().string_prototype();
if (base_value.is_number())
return vm.current_realm()->intrinsics().number_prototype();
if (base_value.is_boolean())
return vm.current_realm()->intrinsics().boolean_prototype();
return base_value.to_object(vm);
}
ThrowCompletionOr<Value> get_by_id(Bytecode::Interpreter& interpreter, IdentifierTableIndex property, Value base_value, Value this_value, u32 cache_index)
{
auto& vm = interpreter.vm();
auto const& name = interpreter.current_executable().get_identifier(property);
auto& cache = interpreter.current_executable().property_lookup_caches[cache_index];
if (base_value.is_string()) {
auto string_value = TRY(base_value.as_string().get(vm, name));
if (string_value.has_value())
return *string_value;
}
auto base_obj = TRY(base_object_for_get(interpreter, base_value));
// OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
// NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
auto& shape = base_obj->shape();
if (&shape == cache.shape
&& (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
return base_obj->get_direct(cache.property_offset.value());
}
CacheablePropertyMetadata cacheable_metadata;
auto value = TRY(base_obj->internal_get(name, this_value, &cacheable_metadata));
if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
cache.shape = shape;
cache.property_offset = cacheable_metadata.property_offset.value();
cache.unique_shape_serial_number = shape.unique_shape_serial_number();
}
return value;
}
ThrowCompletionOr<Value> get_by_value(Bytecode::Interpreter& interpreter, Value base_value, Value property_key_value)
{
auto& vm = interpreter.vm();
auto object = TRY(base_object_for_get(interpreter, base_value));
// OPTIMIZATION: Fast path for simple Int32 indexes in array-like objects.
if (property_key_value.is_int32()
&& property_key_value.as_i32() >= 0
&& !object->may_interfere_with_indexed_property_access()
&& object->indexed_properties().has_index(property_key_value.as_i32())) {
auto value = object->indexed_properties().get(property_key_value.as_i32())->value;
if (!value.is_accessor())
return value;
}
auto property_key = TRY(property_key_value.to_property_key(vm));
if (base_value.is_string()) {
auto string_value = TRY(base_value.as_string().get(vm, property_key));
if (string_value.has_value())
return *string_value;
}
return TRY(object->internal_get(property_key, base_value));
}
ThrowCompletionOr<Value> get_global(Bytecode::Interpreter& interpreter, IdentifierTableIndex identifier, u32 cache_index)
{
auto& vm = interpreter.vm();
auto& realm = *vm.current_realm();
auto& cache = interpreter.current_executable().global_variable_caches[cache_index];
auto& binding_object = realm.global_environment().object_record().binding_object();
auto& declarative_record = realm.global_environment().declarative_record();
// OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
// NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
auto& shape = binding_object.shape();
if (cache.environment_serial_number == declarative_record.environment_serial_number()
&& &shape == cache.shape
&& (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
return binding_object.get_direct(cache.property_offset.value());
}
cache.environment_serial_number = declarative_record.environment_serial_number();
auto const& name = interpreter.current_executable().get_identifier(identifier);
if (vm.running_execution_context().script_or_module.has<NonnullGCPtr<Module>>()) {
// NOTE: GetGlobal is used to access variables stored in the module environment and global environment.
// The module environment is checked first since it precedes the global environment in the environment chain.
auto& module_environment = *vm.running_execution_context().script_or_module.get<NonnullGCPtr<Module>>()->environment();
if (TRY(module_environment.has_binding(name))) {
// TODO: Cache offset of binding value
return TRY(module_environment.get_binding_value(vm, name, vm.in_strict_mode()));
}
}
if (TRY(declarative_record.has_binding(name))) {
// TODO: Cache offset of binding value
return TRY(declarative_record.get_binding_value(vm, name, vm.in_strict_mode()));
}
if (TRY(binding_object.has_property(name))) {
CacheablePropertyMetadata cacheable_metadata;
auto value = TRY(binding_object.internal_get(name, js_undefined(), &cacheable_metadata));
if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
cache.shape = shape;
cache.property_offset = cacheable_metadata.property_offset.value();
cache.unique_shape_serial_number = shape.unique_shape_serial_number();
}
return value;
}
return vm.throw_completion<ReferenceError>(ErrorType::UnknownIdentifier, name);
}
ThrowCompletionOr<void> put_by_property_key(VM& vm, Value base, Value this_value, Value value, PropertyKey name, Op::PropertyKind kind)
{
auto object = TRY(base.to_object(vm));
if (kind == Op::PropertyKind::Getter || kind == Op::PropertyKind::Setter) {
// The generator should only pass us functions for getters and setters.
VERIFY(value.is_function());
}
switch (kind) {
case Op::PropertyKind::Getter: {
auto& function = value.as_function();
if (function.name().is_empty() && is<ECMAScriptFunctionObject>(function))
static_cast<ECMAScriptFunctionObject*>(&function)->set_name(DeprecatedString::formatted("get {}", name));
object->define_direct_accessor(name, &function, nullptr, Attribute::Configurable | Attribute::Enumerable);
break;
}
case Op::PropertyKind::Setter: {
auto& function = value.as_function();
if (function.name().is_empty() && is<ECMAScriptFunctionObject>(function))
static_cast<ECMAScriptFunctionObject*>(&function)->set_name(DeprecatedString::formatted("set {}", name));
object->define_direct_accessor(name, nullptr, &function, Attribute::Configurable | Attribute::Enumerable);
break;
}
case Op::PropertyKind::KeyValue: {
bool succeeded = TRY(object->internal_set(name, value, this_value));
if (!succeeded && vm.in_strict_mode())
return vm.throw_completion<TypeError>(ErrorType::ReferenceNullishSetProperty, name, base.to_string_without_side_effects());
break;
}
case Op::PropertyKind::DirectKeyValue:
object->define_direct_property(name, value, Attribute::Enumerable | Attribute::Writable | Attribute::Configurable);
break;
case Op::PropertyKind::Spread:
TRY(object->copy_data_properties(vm, value, {}));
break;
case Op::PropertyKind::ProtoSetter:
if (value.is_object() || value.is_null())
MUST(object->internal_set_prototype_of(value.is_object() ? &value.as_object() : nullptr));
break;
}
return {};
}
}